Flickering or pulstating Headlights

pt70 said

To add to the confusion, in 1976 Chrysler made 4 alternators that looked the same [square back]. 41 to 65 amps. They also made a 100 amp that looked different [no fins].

They also made 2 different size pulleys [~2 1/2'' and ~3'' diameter].

The full field draw for the square backs is about 5 amps. The full field draw for the old style is 3 amps.

I think the flickering is due to the regulator going from full field to a lesser current and back again. In the past, I'd drive around with the lights on to lessen the flickering.

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The flickering comes from the voltage at the ignition (I) terminal of the regulator varying. Most of the time I find that it's due to the ignition switch contacts being worn or dirty. This is why I feed the regulator (I) terminal from a relay. I disconnect (cut) the wire from the regulator (I) terminal (typically blue) and use it to supply the coil of the relay. I then supply 1 side of the relay contact from the starter relay battery stud (the big stud that goes directly to the positive post of the battery) and then connect the other side of the relay contact to the (I) terminal of the regulator. This will assure a solid and stable voltage at the regulator and will keep your lights from flickering. Additionally the newer style regulator will be more stable than the older style.